Blade lift/centershift controls for motor graders

ABSTRACT

Motor grader blade controls having direct hydraulic blade lift and centershift linkage in cooperation with lateral tilt linkage which may be either fully hydraulic or semihydraulic in its actuation. The linkage is such as to present negligible obstruction to operator visibility of the blade.

United States Patent [191 Johnson et al. a

BLADE LlFT/CENTERSHIFT CONTROLS FOR MOTOR GRADERS Inventors: Harold M.Johnson; Vergil P.

' Hendrickson, both of Decatur, Ill.

Assignee: Caterpillar Tractor Co., Peoria, 111.

Filed: Feb. 2, 1971 Appl. No.: 111,951

US. Cl. 172/793, 172/666 Int. Cl E02f 3/76 Field of Search ReferencesCited UNITED STATES PATENTS 12/1951 MacDonald 172/793 H ae H 44 MW @QEEEJune 19, 1973 6/1962 Vivicr 172/793 5/1970 Ulrich l72/79l X PrimaryExaminer-Robert E. Pulfrey Assistant Examiner-Stephen C. PellegrinoAttorney-Fryer, Tjensvold, Feix, Phillips & Lempio 7 Claims, 6 DrawingFigures PATENIEB 1 9 INVENTORS JOHNSON HAROLD M. VERGIL P. HENDRICKSONATTORNEYS PATENTED Jim I 9 snmanr IuO NO S INVENTORS HAROLD M. JOHNSONVERGlL P. HENDRICKSON (9 d /Azz d- ATTORNEYS PAIENIEBJUNISIBR ,739,361

sum 3 or '3 INVENTORS HAROLD M. JOHNSON VERGIL F! HENDRICKSON BY W4 w,wvw

ATTORNEYS BACKGROUND OF THE INVENTION However, as machines get bigger,experience has indilo cated that mechanical transmission of high forcesor torque loads for blade control purposes is growing increasinglydifficult. For this reason, the current trend has been towardall-hydraulic blade control systems.

However, present hydraulic blade controls typically employ rotary yokearrangements about the forward main frame including a master-slavecylinder mechanism to actuate lock pins engaging the yoke, which permitsselective positioning of the yoke and a lift jack support saddle mountedthereon. The complexity and bulkiness of such lock pin, rotating saddlestructures is disadvantageous in that operator visibility of the bladeis thereby excessively obstructed. In addition, cumbersome release oflock pins and prepositioning of the controls are generally necessary toobtain maximum reach positions with prior art hydraulic blade controlsystems.

SUMMARY OF THE INVENTION The general object of the present invention isto pro vide a relatively compact hydraulic blade lift/centershiftcontrol for motor graders which presents little obstruction to operatorvisibility of the blade. A fully hydraulic centershift lateral tiltlinkage may be incorporated in the control to meet the moresophisticated blade positioning needs of large contractors.Alternatively, a substantially more economical hydraulically actuatedlock pin arrangement may be employed to provide the less sophisticatedcentershift positioning functions required by smaller contractors.

In the accomplishment of the foregoing and other objects and advantages,a blade lift/centershift control in accordance with the presentinvention generally includes a pair of vertically disposed hydrauliclift jacks pivotally connected to a pair of supporting bell cranks formovement about longitudinal and transverse axes, the bell cranks in turnbeing pivotally mounted for movement about longitudinal axes upon a pairof oppositely laterally projecting brackets secured to the oppositesides of the main frame of a motor grader. The rod V ends of the jacksare pivotally connected to oppositely laterally spaced positions of atransverse crossbeam of the grader drawbar. The cranks acting throughthe jacks and their rods thus swing in transverse vertical planes toadjustably support the drawbar, and therefore the blade circle andmoldboard carried thereby.

In addition, means are provided to adjust the pivotal positions of thecranks to obtain extended reach or effectiveness for both lift jacks. Such means may be fully hydraulic or semihydraulic depending on thesophistication of the blade positioning functions required. Finally, thecontrol preferably includes a centershift jack transversely coupledbetween the frame and drawbar to provide positive side shifting of thedrawbar and blade carrying moldboard.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of amotor grader embodying a fully hydraulic blade lift/centershift controlin accordance with the present invention.

FIG. 2 is a sectional view taken at line Il-II of FIG.

FIG. 3 is a view similar to FIG. 2, but of a modified form of thecontrol wherein a hydraulically actuated lock pin arrangement isemployed to accomplish semihydraulic extended reach positioning of theblade in place of fully hydraulic positioning thereof.

FIG. 4 is a sectional view taken at line IV-IV of FIG. 3 illustratingfurther details of the lock pin arrangement.

FIG. 5 is a fragmentary side elevational view of a motor graderembodying another modified form of the blade control arranged for fullyhydraulic actuation.

FIG. 6 is a fragmentary front elevational view of the control of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTIONReferring now to FIGS. 1 and 2 in detail, there is shown a motor grader11 having a main frame 12 and a drawbar 13 with one end connected foruniversal movement to the forward end of the main frame, as indicated at14. At the distal end of the drawbar with respect to universalconnection 14 there are carried a blade circle 16 and moldboard 17 withits associated blade 18 in the conventional manner. By universallycontrolling the position of drawbar 13, corresponding lift andcentershift control of the blade 18 is obtained.

A fully hydraulic blade lift/centershift control in accordance with thepresent invention for accomplishing such universal adjustment of drawbarposition includes a pair of vertically extending hydraulic lift jacks 19and 21 under a pair of supporting bell cranks 22 and 23 pivotallycarried on longitudinal pins 24 and 26 mounted on oppositely laterallyprojecting brackets 27 and 28 secured to the opposite sides of the mainframe 12.

Bell cranks 22 and 23 respectively include angularly related arms 29, 31and 32, 33, and U-brackets 34 and 36 are pivotally connected to arms 29and 32 for movement about longitudinal axes. Brackets 34 and 36 are inturn pivotally connected to the jacks 19 and 21 for movement abouttransverse axes, and the rods 37 and 38 of jacks l9 and 21 are connectedat their ends for pivotal movement about longitudinal axes to theopposite ends of a transverse crossbeam 39 of the drawbar 13.

The drawbar is thus supported by the lift jacks and associated bellcranks, and the cranks swing in vertical transverse planes while thejacks swing in both vertical transverse and vertical longitudinalplanes. By adjusting the rotational positions of the cranks andcorrelatively hydraulically extending and retracting the rods of thehydraulic jacks, a variety of blade lift and centershift positioningfunctions are obtained.

Fully hydraulic actuation of the cranks 22 and 23 to varied rotationalpositions for accomplishing the centershift control functions ispreferably facilitated by means of a complementing centershift positionhydraulic jack 41 and connecting linkage as generally indicated at 42.Linkage 42 includes a bell crank 43 having axially spaced angularlyrelated arms 44 and 46. The crank is journalled in the main frame 12 forrotation about a vertical axis with the arm 44 projecting through atransverse opening in the frame and the arm 46 disposed subjacent same.

Jack 41 is coupled between the frame and arm 44 to impart rotation tocrank 43 in response to hydraulic extension and retraction of the jack.Crank arm 46 is coupled via a link arm 47 to a point adjacent one end ofa cross connecting linkage 48 coupled between the ends of arms 31 and 33of support cranks 22 and 23 to facilitate unitary pivotal movementthereof.

Consequently, responsive to the hydraulically actuated rotation of crank43, support cranks 22 and 23 are unitarily pivoted to tilt the liftjacks 19 and '21 and drawbar 13 thereby supported, to the right or leftdepending upon the sense of rotation of crank 43. In this regard, thelinkage is shifted from the full line to phantom line position depictedin FIG. 2 upon clockwise rotation of crank 43.

To complete the fully hydraulic blade lift/centershift control of thepresent invention as embodied in FIGS. 1 and 2, there is provided acentershift hydraulic jack 49 for positive side shifting of the drawbar13 and blade 18 carried thereby. The head end of jack 49 is coupled bymeans of a ball joint 51 to one end of drawbar crossbeam 39, while therod end of the jack is coupled by means of a ball joint 52 to the centerof the cross connecting link 48 between support cranks 22 and 23.

The head end ofjack 49 may be interchangeably connected to acomplementary ball joint at the opposite end of the drawbar crossbeam.In this regard, the jacks 41 and 49, bell crank 43, and interconnectinglinkage afford most normal centershift positioning, however if a maximum90 vertical angle is to be attained the jack 49 must be connected to theend of the crossbeam toward the desired blade position.

Inasmuch as the fully hydraulic centershift linkage arrangementincluding the jack 41, bell crank 43, and connecting linkage describedhereinbefore is relatively extensive and costly, it is sometimesdesirable for less sophisticated applications that a simplified lesscostly arrangement be substituted therefor. In this regard, reference ismade to FIGS. 3 and 4 which illustrate a selectively adapted,hydraulically actuated lock pin arrangement for accomplishing most ofthe normal centershift positioning functions.

The arrangement includes a lock pin support bracket 53 havinglongitudinally spaced pairs of laterally spaced ears 54 extendingupwardly and outwardly from a body 56. The pairs of ears 54 are adaptedto engage the brackets 27 and 28 for securance thereto by means of thepins 24 and 26, and thereby support the body 56 subjacent the main frame12.

The body 56 is formed with longitudinally spaced transversely extendinggrooves 57 and 58 for slidably receiving spaced apart rail portions 59and 61 of cross connecting link 48. The housing 62 of a hydraulicallyactuated locking pin mechanism 63 is secured to the body 56 of bracket53 subjacent the main frame. A piston 64 is mounted for reciprocationwithin the housing, and a locking pin 66 coaxially secured to the pistonprojects exteriorly of the housing into a bore 67 extending through thebody 56 in intersecting relation to the grooves 57 and 58. A spring 68disposed within the housing normally resiliently urges the pistonwherein the pin traverses groove 57. The pin also traverses one of aplurality of transversely spaced holes 69 provided through the railportions 59 and 61 of link 48, thereby locking same in position.

In this manner, the particular hole engaged by the pin determines theposition of the link and thus the rotational positions of support cranks22 and 23. Upon the introduction of hydraulic pressure to an inlet port71 provided in the housing 62 in communication with a chamber 72 on theopposite side of the piston 64 from spring 68, the piston and pin arehydraulically actuated to a retracted position, as depicted in dashedline in FIG. 4. In this position, the pin is disengaged from any of theholes 69 and the link 48 is thus freed for translational movement.

Upon relaxation of hydraulic pressure, the spring 68 urges the pistonand pin towards the extended positions thereof such that any of theholes 69 in registry with bore 67 is engaged by the pin to lock the link48 in a transverse position determined by the location of the particularengaged hole.

Considering now the manner in which the lock pin arrangement is employedto facilitate lateral adjustment of the blade to extreme side shiftpositions, assume that the pin 66 is initially engaged with thecentermost one of the holes 69 of link 48, as shown in FIG. 3. To effecta lateral blade adjustment it is necessary to rest the blade 18 on theground, release the lock pin, and preposition the cranks 22 and 23 andlink 48 to obtain a maximum side reach condition.

For instance, if it is desired to shift the blade to the far left, as inthe phantom line position of FIG. 3, the

lift jacks 19 and 21 are initially extended sufficiently to rest blade18 upon the ground. Locking pin mechanism 63 is hydraulically actuatedto retract pin 66 and thereby release link 48 for translationalmovement. Jack 19 is then fully extended and jack 21 retracted whichshifts the entire bell crank linkage to the left, through reaction fromthe blades and jacks, sufficiently to register the right hand hole 69 oflink 48 (as viewed in FIG. 3) with bore 67. The pin 66 is now engagedwith this hole by relaxation of hydraulic pressure in the housing 62,thereby locking the link 48 and bell cranks 22 and 23 in the leftshifted position. From this position jacks 19 and 21 are respectivelyretracted and extended to effect the left extended position of the blade18.

Referring now to FIGS. 5 and 6, there will be seen another modified formof blade lift/centershift control in accordance with the presentinvention which is arranged for fully hydraulic actuation as in the caseof the embodiment of FIGS. 1 and 2. In 'the instant case, crank arms 29and 32' are mounted for pivotal movement about longitudinal axes uponoppositely laterally projecting brackets 27 and 28 secured to theopposite I sides of the main frame 12.

U-brackets 34 and 36 are pivotally connected to arms 29 and 32 formovement about longitudinal axes, and the brackets are in turn connectedto lift jacks 19' and 21 for pivotal movement about transverse axes. Therods 37 and 38 ofjacks 19' and 21' are coupled to the opposite ends ofthe transverse crossbeam 39 of drawbar 13. A centershift hydraulic jack49' is coupled between the frame 12 and one end of crossbeam 39 forpositive side shifting of drawbar 13.

To the extent thus far described, it will be appreciated that thecontrol arrangement of FIGS. 5 and 6 is substantially similar to that ofFIGS. 1 and 2. However,

in the present embodiment, fully hydraulic actuation of crank arms 29'and 32 to varied rotational positions is accomplished in a somewhatmodified manner.

More particularly, the crank arms 29' and 32 are radially connected to apair of substantially longitudinal torque tubes 73 and 74 joumalledbetween brackets 27' and 28' and a second set of oppositely laterallyprojecting brackets 76 and 77 secured to frame 12 at a forwardlydisplaced location. A pair of radial crank arms 78 and 79 projectingfrom torque tubes 73 and 74 adjacent brackets 76 and 77 are endconnected to the rods 81 and 82 of a pair of vertical hydraulic jacks 83and 84, the head ends of which are coupled to the bolster of the mainframe 12'. Thus, the jacks 83 and 84 may be actuated to control therotational positions of crank arms 29' and 32' commensurate with avariety of centershift control functions effected by the lift jacks l9and 21'.

Although the invention has been hereinbefore described and illustratedin the accompanying drawings with respect to several preferredembodiments, it is to be noted that various modifications and changesmay be made therein without departing from the true spirit and scope ofthe invention, and thus it is not intended to limit the invention exceptby the terms of the appended claims.

What is claimed is:

1. In a motor grader including a main frame, a drawbar connected at oneend for universal movement to said frame, and a blade carrying moldboardsecured to the distal end of said drawbar with respect to its connectionto said frame, a blade lift/centershift control comprising a pair ofvertically disposed hydraulic lift jacks, a pair of support crankspivotally mounted for movement about longitudinal axes at oppositelylaterally spaced positions of said frame, said cranks having first armsfor connection to said lift jacks, means connecting first ends of saidlift jacks to said crank arms for pivotal movement about longitudinaland transverse axes relative thereto, means coupling second ends of saidlift jacks to oppositely laterally spaced positions of a transversecrossbeam of said drawbar at said distal end thereof, actuatable meansincluding a link between second arms of said cranks respectively and afurther connector means to said frame from said link for adjusting thepivotal positions of said support cranks to obtain extended reachpositions for said lift jacks, and centershift means including a jacktransversely coupled between said actuatable adjusting means and one endof said crossbeam.

2. The combination of claim 1, further defined by said second arms ofthe support cranks being angularly related to the first arms thereof,and the actuatable adjusting means comprising a bell crank having firstand second axially spaced angularly related arms journalled in saidframe for rotation about a vertical axis, a positioning hydraulic jackcoupled between said frame and said first arm of said bell crank toimpart rotation thereto responsive to extension and retraction of saidpositioning jack, and wherein the link coupled between the ends of saidsecond arms of said support cranks effects unitary pivotal movementthereof, and a link arm coupled between said second arm of said bellcrank and one end of said link, whereby hydraulically actuated rotationof said bell crank effects pivotal movement of said support cranks.

3. The combination of claim 1, further defined by the support crankposition adjusting means comprising a pair of longitudinal torque tubesjournalled for rotation on the opposite sides of said frame, saidsupport cranks connected to said torque tubes for rotation therewithwith said arms projecting radially therefrom, a second pair ofradialarms connected to said torque tubes for rotation therewith atpositions forwardly spaced from said first arms, and a second pair ofvertically disposed hydraulic jacks coupled between said frame and saidsecond arms, whereby hydraulically actuated extension and retraction ofsaid second pair of jacks effects pivotal movement of said supportcranks.

4. The combination of claim 1, further defined by said second arms ofthe support cranks being angularly related to the first arms thereof,and the link coupled between the ends of said second arms of saidsupport cranks effecting unitary pivotal movement thereof, and fluidactuated lockpin means carried by said frame for selective lockingengagement with any registering one of a plurality of transverselyspaced holes defined in said cross connecting link.

5. The combination of claim 4, further defined by said lockpin meanscomprising a bracket adapted for securance to said frame with a bodyportion subjacent same, said body portion having at least onetransversely extending groove slidably receiving a rail of said crossconnecting link, said holes of said link extending through said rail,said body portion having a bore transversely intersecting said grooveand registerable with said holes, a piston mounted for reciprocationwithin said housing, a pin coaxially secured to said piston andprojecting exteriorly of said housing through said bore, means springloading said piston to urge same to an extended position wherein saidpin traverses said groove and engages any registering one of said holes,and means for introducing hydraulic pressure to a chamber of saidhousing in opposition to the force of said spring loading means toactuate said piston to a retracted position wherein said pin iswithdrawn from said channel.

6. The combination of claim 2, further defined by said centershifthydraulic jack being coupled between one end of said crossbeam and thecenter of said cross connecting link.

7. The combination of claim 4, further defined by said centershifthydraulic jack being coupled between one end of said crossbeam and thecenter of said cross connecting link.

1. In a motor grader including a main frame, a drawbar connected at oneend for universal movement to said frame, and a blade carrying moldboardsecured to the distal end of said drawbar with respect to its connectionto said frame, a blade lift/centershift control comprising a pair ofvertically disposed hydraulic lift jacks, a pair of support crankspivotAlly mounted for movement about longitudinal axes at oppositelylaterally spaced positions of said frame, said cranks having first armsfor connection to said lift jacks, means connecting first ends of saidlift jacks to said crank arms for pivotal movement about longitudinaland transverse axes relative thereto, means coupling second ends of saidlift jacks to oppositely laterally spaced positions of a transversecrossbeam of said drawbar at said distal end thereof, actuatable meansincluding a link between second arms of said cranks respectively and afurther connector means to said frame from said link for adjusting thepivotal positions of said support cranks to obtain extended reachpositions for said lift jacks, and centershift means including a jacktransversely coupled between said actuatable adjusting means and one endof said crossbeam.
 2. The combination of claim 1, further defined bysaid second arms of the support cranks being angularly related to thefirst arms thereof, and the actuatable adjusting means comprising a bellcrank having first and second axially spaced angularly related armsjournalled in said frame for rotation about a vertical axis, apositioning hydraulic jack coupled between said frame and said first armof said bell crank to impart rotation thereto responsive to extensionand retraction of said positioning jack, and wherein the link coupledbetween the ends of said second arms of said support cranks effectsunitary pivotal movement thereof, and a link arm coupled between saidsecond arm of said bell crank and one end of said link, wherebyhydraulically actuated rotation of said bell crank effects pivotalmovement of said support cranks.
 3. The combination of claim 1, furtherdefined by the support crank position adjusting means comprising a pairof longitudinal torque tubes journalled for rotation on the oppositesides of said frame, said support cranks connected to said torque tubesfor rotation therewith with said arms projecting radially therefrom, asecond pair of radial arms connected to said torque tubes for rotationtherewith at positions forwardly spaced from said first arms, and asecond pair of vertically disposed hydraulic jacks coupled between saidframe and said second arms, whereby hydraulically actuated extension andretraction of said second pair of jacks effects pivotal movement of saidsupport cranks.
 4. The combination of claim 1, further defined by saidsecond arms of the support cranks being angularly related to the firstarms thereof, and the link coupled between the ends of said second armsof said support cranks effecting unitary pivotal movement thereof, andfluid actuated lockpin means carried by said frame for selective lockingengagement with any registering one of a plurality of transverselyspaced holes defined in said cross connecting link.
 5. The combinationof claim 4, further defined by said lockpin means comprising a bracketadapted for securance to said frame with a body portion subjacent same,said body portion having at least one transversely extending grooveslidably receiving a rail of said cross connecting link, said holes ofsaid link extending through said rail, said body portion having a boretransversely intersecting said groove and registerable with said holes,a piston mounted for reciprocation within said housing, a pin coaxiallysecured to said piston and projecting exteriorly of said housing throughsaid bore, means spring loading said piston to urge same to an extendedposition wherein said pin traverses said groove and engages anyregistering one of said holes, and means for introducing hydraulicpressure to a chamber of said housing in opposition to the force of saidspring loading means to actuate said piston to a retracted positionwherein said pin is withdrawn from said channel.
 6. The combination ofclaim 2, further defined by said centershift hydraulic jack beingcoupled between one end of said crossbeam and the center of said crossconnecting link.
 7. The combination of claim 4, further defined by saidcentershift hydraulic jack being coupled between one end of saidcrossbeam and the center of said cross connecting link.